Cotton lint yield, fiber quality, and water-use efficiency as influenced by cultivar and irrigation level

Cotton is produced in the Texas High Plains under a wide range of water levels, ranging from dryland (rainfed) to full irrigation, with irrigation levels that depend on well capacities. With declining pumping capacities, it is important to maximize water-use efficiency (WUE) through crop management and cultivar selection. The objectives of this research were to 1) evaluate the lint yield and fiber quality of current commercial and experimental cotton cultivars, 2) determine the WUE of these cultivars in different irrigation settings 3) identify the returns above cost for each cultivar within irrigation treatments, and 4) determine which cultivar is best for producers with varying levels of irrigation water and risk preference on the Texas High Plains. Field studies were conducted in 2011 and 2012 to evaluate new cultivars under varying irrigation inputs at Lamesa and Lubbock, TX. The experimental design at both locations was a split plot design with irrigation as the main effect and cultivar as the split effect. Eight cultivars [DP 0912 B2RF, DP 1032 B2RF, DP 1044 B2RF, DP 1212 B2RF, DP 1219 B2RF, 11R110B2R2, 11R112B2R2 (DP 1321 B2RF), and 11R159B2R2 (DP 1359 B2RF)] and four irrigation levels, replicated three times were evaluated in 2011 at Lubbock and Lamesa. Target irrigation levels were 0, 30, 60, and 90% ET replacement. In 2012, twelve cultivars with four replications were evaluated including the eight from 2011. The four additional experimental cultivars included: 11R124B2R2 (DP 1311 B2RF), 11R136B2R2, 11R154B2R2, and 12R242B2R2. Due to the excessive temperatures and drought conditions experienced in 2011, a reduction in yield and fiber quality was seen at both locations. At both locations in both years, increased yields were produced at increased irrigation levels; however, no cultivar by irrigation level interaction was observed. In 2012 at Lamesa, WUE declined as irrigation increased while no differences in WUE between irrigation levels were observed in Lubbock. Over all four trials, no cultivar by irrigation interaction for WUE was observed. Staple length tended to increase as irrigation increased, while the relationship of other fiber quality parameters was less pronounced. Net returns varied among cultivars, and influenced which cultivars were preferred by producers with different risk preferences. In both years at Lubbock, DP 1321 B2RF was the most preferred cultivar for risk averse producers, while DP 1219 B2RF and DP 1359 B2RF were among the most preferred cultivars for risk averse producers in three out of the four trials. In both 2012 locations, 11R136B2R2 had fiber length greater than or equal to all other cultivars.